There has been a widespread use of the printing apparatus (hereinafter referred to as “image forming apparatus) of a multi-functional peripheral provided with a printer function and a scanner function. When this mage forming apparatus is used for printing operation, a print job of page description language (PDL: Page Description Language) format is received from the client linked to the network, and the print job is raterized (bit map expansion) to generate multivalued (e.g., 8 bits) image data. This multivalued image data is screened (binarized) to generate binary image data, and image adjustment processing is applied to the binary image data, which is then outputted onto a paper medium.
In the system connected with a plurality of image forming apparatuses via the network, if the process of generating multivalued image data from a print job (hereinafter referred to as “RIP (Raster Image Processor) processing”) or the process of screening the multivalued image data is to be performed in each image forming apparatus, each image forming apparatus is required to have the functions of performing the above-mentioned processes. This will result in a complicated structure of the image forming apparatus. To avoid this, this system is designed in such a structure that a print controller provided with the above-mentioned RIP processing function and screening function is linked with the network, and the print controller exclusively takes charge of the above-mentioned processes (e.g., Japanese Unexamined Patent Application Publication No. 2005-292999).
FIG. 8 schematically shows the structure of the image forming system provided with such a print controller. A client 40 and print controller 30 are connected via such a second line 60 as LAN (Local Area Network) or WAN (Wide Area Network), while a print controller 30 and image forming apparatus 20 are connected via such a first line 50 as a dedicated bus.
The print controller 30 receives a print job of page description language format from the client 40 through the second line 60, and applies RIP processing or screening processing. The binary image data and job ticket are then sent to the image forming apparatus 20 via the first line 50. In the image forming apparatus 20, image adjustment processing is applied to the binary image data, and printing is carried out.
Normally, the print controller 30 is not provided with a display section or operation section. Thus, the panel of the image forming apparatus 20 must be used to set the IP (Internet Protocol) address of the print controller 30, to register the information of the image forming apparatus 20 or user information into the print controller 30, to control the print job, and to update the program of the print controller 30. This involves the following problems:
In the first place, when the print controller 30 is controlled from the panel of the image forming apparatus 20, the control signal (command code) is transferred via the first line 50 such as the above-mentioned dedicated bus. This first line 50 is a line used to transfer the image data when the print job is executed. Accordingly, the image data concurs with the command code in the first line 50 and image data transfer performance is reduced, with the result that effective printing operation cannot be performed.
Further, when the screen for controlling the print controller 30 is to be displayed on the panel of the image forming apparatus 20, if screen data is sent from the print controller 30 to the image forming apparatus 20 via the first line 50, the image data competes with the screen data in the first line 50, and the image data transfer performance is further reduced. Moreover, a special-purpose GUI (Graphical User Interface) is mounted on the image forming apparatus 20, and the screen suited for the control of each print controller 30 is created by the image forming apparatus 20. Use of such a structure will increase the number of man hours for designing the screen, and a bug will be produced by differences in the program interface. Further, this structure will make it difficult to modify the screen structure after shipment of the image forming apparatus 20, and the screen will have to be created again when the print controller 30 is modified. These problems will arise to cause difficulties in the effective control of the print controller.
In view of the problems described above, it is the major object of the present invention to provide an image forming system and control method capable of efficient printing operation and effective control of the print controller.